Physics Commons^™

Helium Nanodroplets As An Efficient Tool To Investigate Hydrogen Attachment To Alkali Cations, Siegfried Kollotzek, José Campos-Martínez, Massimiliano Bartolomei, Fernando Pirani, Lukas Tiefenthaler, Marta I. Hernández, Teresa Lázaro, Eva Zunzunegui-Bru, Tomás González-Lezana, José Bretón, Javier Hernández-Rojas, Olof E. Echt, Paul Scheier

Faculty Publications

We report a novel method to reversibly attach and detach hydrogen molecules to positively charged sodium clusters formed inside a helium nanodroplet host matrix. It is based on the controlled production of multiply charged helium droplets which, after picking up sodium atoms and exposure to H₂ vapor, lead to the formation of Na_m⁺(H₂)_n clusters, whose population was accurately measured using a time-of-flight mass spectrometer. The mass spectra reveal particularly favorable Na⁺(H₂)_n and Na₂⁺(H₂)_n clusters for specific “magic” numbers of attached hydrogen molecules. …

Solvation Of Large Polycyclic Aromatic Hydrocarbons In Helium: Cationic And Anionic Hexabenzocoronene, Miriam Kappe, Florent Calvo, Johannes Schöntag, Holger F. Bettinger, Serge Krasnokutski, Martin Kuhn, Elisabeth Gruber, Fabio Zappa, Paul Scheier, Olof E. Echt

Faculty Publications

The adsorption of helium on charged hexabenzocoronene (Hbc, C₄₂H₁₈), a planar polycyclic aromatic hydrocarbon (PAH) molecule of D_6h symmetry, is investigated by a combination of high-resolution mass spectrometry and classical and quantum computational methods. The ion abundance of He_nHbc⁺ complexes versus size n features prominent local anomalies at n = 14, 38, 68, 82, and a weak one at 26, indicating that for these “magic” sizes the helium evaporation energies are relatively large. Surprisingly, mass spectra of anionic He_nHbc^– complexes feature a different set of anomalies, namely at …

Microstructural Origin Of The High-Energy Storage Performance In Epitaxial Lead-Free Ba(Zr 0.2 Ti 0.8 )O 3 Thick Films, Jun Ouyang, Xianke Wang, Changtao Shao, Hongbo Cheng, Hanfei Zhu, Yuhang Ren

Publications and Research

In our previous work, epitaxial Ba(Zr 0.2 Ti 0.8 )O 3 thick films (~1–2 μ m) showed an excellent energy storage performance with a large recyclable energy density (~58 J/cc) and a high energy efficiency (~92%), which was attributed to a nanoscale entangled heterophase polydomain structure. Here, we propose a detailed analysis of the structure–property relationship in these film materials, using an annealing process to illustrate the effect of nanodomain entanglement on the energy storage performance. It is revealed that an annealing-induced stress relaxation led to the segregation of the nanodomains (via detailed XRD analyses), and a degraded energy storage …

Adsorption Of Helium And Hydrogen On Triphenylene And 1,3,5-Triphenylbenzene, Bergmeister Bergmeister, Kollotzek Kollotzek, Florent Calvo, Elisabeth Gruber, Fabio Zappa, Paul Scheier, Olof E. Echt

Faculty Publications

The adsorption of helium or hydrogen on cationic triphenylene (TPL, C₁₈H₁₂), a planar polycyclic aromatic hydrocarbon (PAH) molecule, and of helium on cationic 1,3,5-triphenylbenzene (TPB, C₂₄H₁₈), a propeller-shaped PAH, is studied by a combination of high-resolution mass spectrometry and classical and quantum computational methods. Mass spectra indicate that He_nTPL⁺ complexes are particularly stable if n = 2 or 6, in good agreement with the quantum calculations which show that for these sizes the helium atoms are strongly localized on either side of the central carbon ring for n = …

Quantification Of Spent Coffee Ground Extracts By Roast And Brew Method, And Their Utility In A Green Synthesis Of Gold And Silver Nanoparticles, Brian G Yust, Niny Z Rao, Evan T Schwarzmann, Madisyn H Peoples

College of Life Sciences Faculty Papers

Nanotechnology has become increasingly important in modern society, and nanoparticles are routinely used in many areas of technology, industry, and commercial products. Many species of nanoparticle (NP) are typically synthesized using toxic or hazardous chemicals, making these methods less environmentally friendly. Consequently, there has been growing interest in green synthesis methods, which avoid unnecessary exposure to toxic chemicals and reduce harmful waste. Synthesis methods which utilize food waste products are particularly attractive because they add value and a secondary use for material which would otherwise be disposed of. Here, we show that spent coffee grounds (SCGs) that have already been …

Bbt Acoustic Alternative Top Bracing Cadd Data Set-Norev-2022jun28, Bill Hemphill

STEM Guitar Project’s BBT Acoustic Kit

This electronic document file set consists of an overview presentation (PDF-formatted) file and companion video (MP4) and CADD files (DWG & DXF) for laser cutting the ETSU-developed alternate top bracing designs and marking templates for the STEM Guitar Project’s BBT (OM-sized) standard acoustic guitar kit. The three (3) alternative BBT top bracing designs in this release are
(a) a one-piece base for the standard kit's (Martin-style) bracing,
(b) 277 Ladder-style bracing, and
(c) an X-braced fan-style bracing similar to traditional European or so-called 'classical' acoustic guitars.

The CADD data set for each of the three (3) top bracing designs includes …

Evaluation Of Silver Nanoparticles Attached To Methylene Blue As An Antimicrobial Agent And Its Cytotoxicity, Somon Hakimov

Masters Theses & Specialist Projects

Antibiotics resistance is considered as one of the greatest public health challenges of our time. In this work, we have synthesized silver nanoparticles (Ag NPs) using pulsed liquid ablation in different medium of growth and later combined with methylene blue (MB) to evaluate its potential as an effective photodynamic therapy agent. Ag NPs were synthesized by pulsed laser ablation technique in Polyvinylpyrrolidone (PVP), citrate, and Polyvinyl alcohol (PVA). The Ag NPs were characterized using transmission electron microscopy (TEM), UV-Visible (UV-Vis), and photoluminescence (PL) spectra. Next, Ag NPs were coupled with MB and used to deactivate the Gram-negative bacteria, Escherichia coli …

Bbt Side Mold Assy, Bill Hemphill

STEM Guitar Project’s BBT Acoustic Kit

This electronic document file set covers the design and fabrication information of the ETSU Guitar Building Project’s BBT (OM-sized) Side Mold Assy for use with the STEM Guitar Project’s standard acoustic guitar kit. The extended 'as built' data set contains an overview file and companion video, the 'parent' CADD drawing, CADD data for laser etching and cutting a drill &/or layout template, CADD drawings in AutoCAD .DWG and .DXF R12 formats of the centerline tool paths for creating the mold assembly pieces on an AXYZ CNC router, and support documentation for CAM applications including router bit specifications, feeds, speed, multi-pass …

Stabilization Of Phenanthrene Anions In Helium Nanodroplets, Siegfried Kollotzek, Farhad Izadi, Miriam Meyer, Stefan Bergmeister, Fabio Zappa, Stephan Denifl, Olof E. Echt, Paul Scheier, Elisabeth Gruber

Faculty Publications

It has been debated for years if the polycyclic aromatic hydrocarbon phenanthrene exists in its anionic form, or, in other words, if its electron affinity (EA) is positive or negative. In this contribution we confirm that the bare phenanthrene anion Ph^- created in a binary collision with an electron at room temperature has a lifetime shorter than microseconds. However, the embedding of neutral phenanthrene molecules in negatively charged helium nanodroplets enables the formation of phenanthrene anions by charge transfer processes and the stabilization of the latter in the ultracold environment. Gentle shrinking of the helium matrix of phenanthrene-doped HNDs …

Stem Club, Camden Jones, Erica Gesner, Amber Gadeken

Honors Expanded Learning Clubs

The goal of this club is to introduce various topics stemming from different fields in science. We hope to excite the students about science and show them how important it is to their everyday lives. This club also aims to provide free education to underserved communities.

Hands-On Stem: Chemistry, Physics, And Other Science Resources For K-12 Education, Lisa Ahlberg, G. Brendan Cross

Faculty Publications

No abstract provided.

Controlling Unequal Surface Energy Results Caused By Test Liquids: The Case Of Uv/O3 Treated Pet, Bilge N. Altay, Paul D. Fleming, Md Arifur Rahman, Alexandra Pekarovicova, Bruce Myers, Cem Aydemir, Arif Karademir

Articles

Ultraviolet/ozone (UV/O3) treatment has been reported to be an effective method to modify properties such as wettability, adhesion or adsorption of plastic surfaces. The change in the surface is measured by contact angle analysis, which employs liquids and their surface tensions (ST) to estimate the surface energy (SE). We found two different practices in the scientific community: (1) the majority of researchers adopted the ST value of liquids from the literature, while (2) other researchers conducted real-time measurements in the lab under ambient conditions prior to SE estimation. To the best of our knowledge, there is no study that compares …

Volume 13, Payton Davenport, Audrey Lemons, Jacob Shope, Haley Smith, Cassandra Poole, Rachel Cannon, Rachel Boch, Suzanne Stetson

Incite: The Journal of Undergraduate Scholarship

Introduction Dr. Roger A. Byrne, Dean

From the Editor Dr. Larissa “Kat” Tracy

From the Designers Rachel English, Rachel Hanson

The Effect of Compliment Type on the Estimated Value of the Compliment by Payton Davenport, Audrey Lemons, and Jacob Shope

The Imperial Japanese Military: A New Identity in the Twentieth Century, 1853–1922 by Haley Smith

Longwood University’s campus: Human-cultivated Soil has Higher Microbial Diversity than Soil Collected from Wild Sites by Cassandra Poole

Reminiscent Modernism: Poetry Magazine’s Modernist Nostalgia for the Past by Rachel Cannon

Challenges Faced by Healthcare Workers During the COVID-19 Pandemic: A Preliminary Study of Age and …

Building-Block Approach To The Discovery Of Na8mn2(Ge2se6)2: A Polar Chalcogenide Exhibiting Promising Harmonic Generation Signals With A High Laser-Induced Damage Threshold, Srikanth Balijapelly, Andrew J. Craig, Jeong Bin Cho, Joon I. Jang, Kartik Ghosh, Jennifer A. Aitken, Aleksandr V. Chernatynskiy, Amitava Choudhury

Physics Faculty Research & Creative Works

A new polar quaternary chalcogenide, Na8Mn2(Ge2Se6)2, has been synthesized using the building-block approach by reacting preformed Na6Ge2Se6 and MnCl2 at 750 °C. The structure consists of layers of [Na(1)Mn(Ge2Se6)]3– stacked perpendicular to the c-axis and sodium ions occupying the interlayer space. An indirect bandgap of 1.52 eV has been calculated using density functional theory, which is expectedly underestimated compared to the observed optical bandgap of 1.95 eV derived from diffuse reflectance spectroscopic measurements in the UV/Vis/NIR region. Magnetic measurements confirm the paramagnetic nature of Na8Mn2(Ge2Se6)2 with an experimental magnetic moment of 5.8 μB in good agreement with the theoretical spin …

Limits Of Detection Of Mycotoxins By Laminar Flow Strips: A Review, Xinyi Zhao, Hugh Byrne, Christine M. O’Connor, James Curtin, Furong Tian

Articles

Mycotoxins are secondary metabolic products of fungi. They are poisonous, carcinogenic, and mutagenic in nature and pose a serious health threat to both humans and animals, causing severe illnesses and even death. Rapid, simple and low-cost methods of detection of mycotoxins are of immense importance and in great demand in the food and beverage industry, as well as in agriculture and environmental monitoring, and, for this purpose, lateral flow immunochromatographic strips (ICSTs) have been widely used in food safety and environmental monitoring. The literature to date describing the development of ICSTs for the detection of different types of mycotoxins using …

Phenanthrene: Establishing Lower And Upper Bounds To The Binding Energy Of A Very Weakly Bound Anion, Elisabeth Gruber, Siegfried Kollotzek, Stefan Bergmeister, Fabio Zappa, Milan Ončák, Paul Scheier, Olof E. Echt

Faculty Publications

Quite a few molecules do not form stable anions that survive the time needed for their detection; their electron affinities (EA) are either very small or negative. How does one measure the EA if the anion cannot be observed? Or, at least, can one establish lower and upper bounds to their EA? We propose two approaches that provide lower and upper bounds. We choose the phenanthrene (Ph) molecule whose EA is controversial. Through competition between helium evaporation and electron detachment in He_nPh^- clusters, formed in helium nanodroplets, we estimate the lower bound of the vertical detachment energy …

A Microfluidic Approach For Synthesis And Kinetic Profiling Of Branched Gold Nanostructures, Qi Cai, Valentina Castagnola, Luca Boselli, Alirio Moura, Hender Lopez, Wei Zhang, João M. De Araújo, Kenneth A. Dawson

Articles

Automatized approaches for nanoparticle synthesis and characterization represent a great asset to their applicability in the biomedical field by improving reproducibility and standardization, which help to meet the selection criteria of regulatory authorities. The scaled-up production of nanoparticles with carefully defined characteristics, including intrinsic morphological features, and minimal intra-batch, batch-to-batch, and operator variability, is an urgent requirement to elevate nanotechnology towards more trustable biological and technological applications. In this work, microfluidic approaches were employed to achieve fast mixing and good reproducibility in synthesizing a variety of gold nanostructures. The microfluidic setup allowed exploiting spatial resolution to investigate the growth evolution …

Resolving The Three-Dimensional Rotational And Translational Dynamics Of Single Molecules Using Radially And Azimuthally Polarized Fluorescence, Oumeng Zhang, Weiyan Zhou, Jin Lu, Tingting Wu, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

We report a radially and azimuthally polarized (raPol) microscope for high detection and estimation performance in single-molecule orientation-localization microscopy (SMOLM). With 5000 photons detected from Nile red (NR) transiently bound within supported lipid bilayers (SLBs), raPol SMOLM achieves 2.9 nm localization precision, 1.5° orientation precision, and 0.17 sr precision in estimating rotational wobble. Within DPPC SLBs, SMOLM imaging reveals the existence of randomly oriented binding pockets that prevent NR from freely exploring all orientations. Treating the SLBs with cholesterol-loaded methyl-β-cyclodextrin (MβCD-chol) causes NR’s orientational diffusion to be dramatically reduced, but curiously NR’s median lateral displacements drastically increase from 20.8 to …

Development Of Scent Detection And Categorization Algorithm Using Gas Chromatography And Machine Learning, Alex Driehaus

Mahurin Honors College Capstone Experience/Thesis Projects

There are many looking to connect human senses to quantifiable data. Scents are categorized by their descriptions into scent families. These include citrus, floral, and woody. Similar descriptors designate similar families, while different descriptors correlate with different families. Dravnieks compiled an Atlas of chemical descriptors [1]. Such descriptors are cinnamon, fruity, and cadaverous. By analyzing the applicability of these descriptors, the chemicals will be sorted into their scent families.

Gas chromatography generates sample-specific signals of voltage over time. Chromatograms of known scents will serve as a basis for a convolutional neural network. This algorithm will be trained on these signals …

Stratospheric Aerosol Composition Observed By The Atmospheric Chemistry Experiment Following The 2019 Raikoke Eruption, Chris D. Boone, Peter F. Bernath, Keith Labelle, Jeff Crouse

Chemistry & Biochemistry Faculty Publications

Infrared aerosol spectra derived from Atmospheric Chemistry Experiment measurements following the June 2019 Raikoke volcanic eruption are used to evaluate the composition of stratospheric aerosols in the Arctic. A blanket of aerosols, spanning an altitude range from the tropopause (8–11 km) to 20 km, persisted in the stratosphere over northern latitudes for many months. The aerosols within this blanket were almost exclusively sulfates. The percentage of sulfuric acid in the aerosols decreased over time, dropping below 50% H₂SO₄ concentration at some altitudes by March 2020. Contrary to previous reports, the aerosol blanket was not comprised of smoke …

A Local Mode Study Of Ring Puckering Effects In The Infrared Spectra Of Cyclopentane, Edwin L. Sibert Iii, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

We report and interpret recently recorded high-resolution infrared spectra for the fundamentals of the CH₂ scissors and CH stretches of gas phase cyclopentane at −26.1 and −50 ^○C, respectively. We extend previous theoretical studies of this molecule, which is known to undergo barrierless pseudorotation due to ring puckering, by constructing local mode Hamiltonians of the stretching and scissor vibrations for which the frequencies, couplings, and linear dipoles are calculated as functions of the pseudorotation angle using B3LYP/6-311++(d,p) and MP2/cc-pVTZ levels of theory. Symmetrization (D_5h) of the vibrational basis sets leads to simple vibration/pseudorotation Hamiltonians whose solutions …

Charge Transfer Mediated Triplet Excited State Formation In Donor-Acceptor-Donor Bodipy: Application For Recording Of Holographic Structures In Photopolymerizable Glass, Tatsiana Mikulchyk, Safakath Karuthedath, Catherine S.P. De Castro, Andrey A. Buglak, Aimee Sheehan, Aaron Wieder, FréDéRic Laquai, Izabela Naydenova, Mikhail Filatov

Articles

Donor–acceptor–donor BODIPY triads bearing anthracene or pyrene as electron donating subunits were prepared through a stepwise synthesis. Photoinduced electron transfer and formation of long-lived triplet excited states via spin–orbit charge transfer intersystem crossing (SOCT-ISC) was studied by steady-state and ultrafast pump-probe spectroscopy and further supported by DFT computations. New BODIPYs were found to form triplet states and sensitize singlet oxygen in both polar and non-polar solvents which is unusual for photosensitizers operating via SOCT-ISC. BODIPY-anthracene triad (ABA) was used as a photosensitizer component in a photopolymerizable glass that was prepared by a four-step sol–gel process. ABA in combination with N …

The Hitran2020 Molecular Spectroscopic Database, I. E. Gordon, L. S. Rothman, R. J. Hargreaves, R. Hashemi, E. V. Karlovets, F. M. Skinner, E. K. Conway, C. Hill, R. V. Kochanov, Y. Tan, P. Wcisło, A.A. Finenko, K. Nelson, P. F. Bernath, M. Birk, V. Boudon, A. Campargue, K. V. Chance, A. Coustenis, B. J. Drouin, J.-M. Flaud, R. R. Gamache, J. T. Hodges, D. Jacquemart, E. J. Mlawer, A. V. Nikitin, V.I. Perevalov, M. Rotger, J. Tennyson, G. C. Toon, H. Tran, V. G. Tyuterev, E. M. Adkins, A. Baker, A. Barbe, E. Canè, A. G. Császár, A. Dudaryonok, O. Egorov, A. J. Fleisher, H. Fleurbaey, A. Foltynowicz, T. Furtenbacher, J. J. Harrison, J.M. Hartmann, V.- M. Horneman, X. Huang, T. Karman, J. Karns, S. Kassi, I. Kleiner, V. Kofman, F. Kwabia-Tchana, N.N. Lavrentieva, T. J. Lee, D. A. Long, A. A. Lukashevskaya, O. M. Lyulin, V. Yu Makhnev, W. Matt, S. T. Massie, M. Melosso, S. N. Mikhailenko, D. Mondelain, H.S.P. Müller, O. V. Naumenko, A. Perrin, O. L. Polyansky, E. Raddaoui, P. L. Raston, Z. D. Reed, M. Rey, C. Richard, R. Tóbiás, I. Sadiek, D. W. Schwenke, E. Starikova, K. Sung, F. Tamassia, S. A. Tashkun, J. Vander Auwera, I.A. Vasilenko, A.A. Vigasin, G.L. Villanueva, B. Vispoel, G. Wagner, A. Yachmenev, S. N. Yurchenko

Chemistry & Biochemistry Faculty Publications

The HITRAN database is a compilation of molecular spectroscopic parameters. It was established in the early 1970s and is used by various computer codes to predict and simulate the transmission and emission of light in gaseous media (with an emphasis on terrestrial and planetary atmospheres). The HITRAN compilation is composed of five major components: the line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, experimental infrared absorption cross-sections (for molecules where it is not yet feasible for representation in a line-by-line form), collision-induced absorption data, aerosol indices of refraction, and general tables (including partition sums) that apply globally to the data. …